USGS Volcano Hazards Program Volcano Update

Activity Summary: Kilauea continued to erupt at two locations: At the summit, DI inflation slowed and the lava lake level overflowed the inner ledge before dropping below it early this morning; the lake level has resumed its rise as of this posting. At Pu`u `O`o crater, lava flows issued from several sources; one of the flows was advancing down the cone's east flank this morning. To the southeast of Pu`u `O`o, a lava flow was entering the ocean in multiple areas both inside and outside the National Park boundary while additional lava flows were active to the west on the coastal plain. Gas emissions remained elevated.

Recent Observations at Kilauea summit: The summit tiltmeter network recorded slowing DI inflation while the lava lake level continued to rise, overflowing onto the inner ledge most of yesterday to a high point of 27 m (89 ft) below the Halema`uma`u Crater floor at about 2 am before dropping back below the inner ledge; as of this posting, the lake level is rising again and starting to overflow onto the inner ledge. The most recent (preliminary) sulfur dioxide emission rate measurement was 600 tonnes/day on January 10, 2013; this value is a typical background emission rate between rise/fall events; new measurements must await the return of moderate trade winds. A very small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair) was likely carried out of the vent in the gas plume and deposited on nearby surfaces.

Seismic tremor levels were low with a drop in high-frequency tremor after 4 am this morning; this was similar to a rise/fall event except that the lava lake level did not remain elevated as expected. Ten earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours: 1 beneath the west edge of the summit caldera, 6 south of the summit caldera, 2 within the upper east rift zone, and 1 on south flank faults.

Background: The summit lava lake is deep within an ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. The surface level of the lava lake has remained mostly below the inner ledge (~31 m or 100 ft below the floor of Halema`uma`u Crater on October 29, 2012) and has risen above and flooded the ledge in October, 2012, and January, 2013. The lake level responds to summit tilt changes with the lake receding during deflation and rising during inflation.

Recent Observations at the middle east rift zone vents: Lava activity continued on the coastal plain with no significant changes. An approximately 1 km-wide (0.6 mi wide) lava flow remained active on the coastal plain with minimal surface activity straddling the easternmost boundary of Hawai`i Volcanoes National Park at the coast and entering the ocean at several locations, both inside and outside Hawai`i Volcanoes National Park. To the west, flows remained active, but not advancing, near the base of the pali.

HAZARD ALERT:Lava entering the ocean builds lava deltas. The lava delta and adjacent areas are some of the most hazardous areas on the flow field. Frequent delta/bench collapses give little warning, can produce explosions capable of throwing both dense and molten rocks hundreds of meters (yards) in all directions (inland as well as out to sea), and can produce damaging local waves. The steam plume produced by lava entering the ocean contains fine lava fragments and an assortment of acid droplets that can be harmful to your health. The rapidly changing conditions near the ocean entry have been responsible for many injuries and a few deaths.

The tiltmeter on the north flank of Pu`u `O`o cone recorded minor fluctuations with no clear trend. Lava levels at Pu`u `O`o were again high with lava issuing almost continuously from the southeast spatter cone. The lava lake at the northeast edge of the crater floor, which is perched higher than the east rim of Pu`u `O`o crater, started to overflow about 10:30 am yesterday on its east side sending a lava flow onto the east flank of Pu`u `O`o cone that continued to be actively advancing eastward through this morning. Seismic tremor levels near Pu`u `O`o remained low. The most recent (preliminary) sulfur dioxide emission rate measurement was 250 tonnes/day on January 7, 2013, from all east rift zone sources.

Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Pu`u `O`o Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December 2011. Since late December 2011, the flows have remained intermittently active on the pali and the coastal plain and finally re-entered the ocean starting on November 24, 2012. In general, activity waxes with inflation and wanes with deflation.

Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Lava deltas, which can collapse into the ocean without warning, are extremely hazardous and should be avoided (see HAZARD ALERT above). Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:East rift zone flow field - Most of the flow field is within the closed-access Kahauale'a Natural Area Reserve (NAR) and the abandoned Royal Gardens subdivision and can only be viewed from the air. A small part of the western flow field near the coast in within Hawai`i Volcanoes National Park (see below for access info). Under favorable weather conditions, active flows-when present-can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093). Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.